The field of the present invention relates to archery bows. In particular, a compound archery bow is described herein wherein a power cable is simultaneously taken up at one end and let out at the other using an eccentric let-out mechanism.
For purposes of the present disclosure and appended claims, the terms “compound archery bow” or “compound bow” shall denote an archery bow that uses a levering system, usually comprising one or more cables and pulleys, to bend the limbs as the bow is drawn. Examples of compound bows include dual-cam bows (including those that employ a Binary Cam System®), hybrid-cam bows, or single-cam bows. Many compound archery bows typically include one or more power cables (sometimes referred to as buss cables or anchor cables). Conventionally, each power cable is engaged at its first end to be taken up by a power cam (or other take-up mechanism) of a pulley member rotatably mounted on one bow limb, and is coupled at its second end to the other bow limb. Tension developed as the bow is drawn and the power cable is taken up causes deformation of the bow limbs and storage of potential energy therein. A portion of that potential energy is transformed into the kinetic energy of the arrow shot by the bow. A few examples of various compound bow types are disclosed in the following patents and application, all of which are incorporated by reference as if fully set forth herein:
U.S. Pat. No. 3,990,425 entitled “Compound bow” issued Nov. 9, 1976 to Ketchum;
U.S. Pat. No. 4,686,955 entitled “Compound archery bows” issued Aug. 18, 1987 to Larson;
U.S. Pat. No. 5,368,006 entitled “Dual-feed single-cam compound bow” issued Nov. 29, 1994 to McPherson;
U.S. Pat. No. 6,871,643 entitled “Eccentric elements for a compound archery bow” issued Mar. 29, 2005 to Cooper et al;
U.S. Pat. No. 6,990,970 entitled “Compound archery bow” issued Jan. 31, 2006 to Darlington;
U.S. Pat. No. 7,305,979 entitled “Dual-cam archery bow with simultaneous power cable take-up and let-out” issued Dec. 11, 2007 to Yehle;
U.S. Pat. No. 7,441,555 entitled “Synchronized compound archery bow” issued Oct. 28, 2008 to Larson; and
U.S. non-provisional application Ser. No. 12/511,085 entitled “Pulley-and-cable power cable tensioning mechanism for a compound archery bow” filed Jul. 29, 2009 in the name of Craig T. Yehle.
In some single-cam, dual-cam, and hybrid-cam compound bows, the power cable is connected at its second end directly to a bow limb or to an axle on which a pulley member is mounted on the bow limb. Such a direct connection can include a split power cable arrangement (wherein the second end of the power cable is divided into two discrete end segments each secured to the limb or axle) or a yoke arrangement (wherein the power cable is attached to a yoke member that is in turn attached to the limb or axle by two yoke cables or by a single looped yoke cable). If a yoke arrangement is employed, the yoke cable(s) can be secured on opposite sides of a pulley member between the pulley member and the limb, or on opposite sides of the limb. If secured between the pulley member and the limb, the spacing provided by the yoke enables rotation of the pulley member without interference from the yoke cable(s). If a split power cable arrangement is employed, the discrete end segments of the split power cable are often secured on opposite sides of the limb to enable rotation of the pulley member without interference from the power cable end segments, but can in some instances be secured between the pulley member and the limb.
Examples of a yoke arrangement for a compound bow cable are disclosed in the following patents, all of which are incorporated by reference as if fully set forth herein:
U.S. Pat. No. 4,330,521 entitled “Compound bow” issued Nov. 17, 1981 to Schmitt;
U.S. Pat. No. 4,440,142 entitled “Compound bow cable tension adjuster” issued Apr. 3, 1984 to Simonds;
U.S. Pat. No. 4,546,754 entitled “Yoke anchor for a compound bow” issued Oct. 15, 1985 to Smith;
U.S. Pat. No. 4,733,648 entitled “Compound bow cable anchor” issued Mar. 29, 1988 to Martin;
U.S. Pat. No. 4,781,167 entitled “Compound bow with adjustable tension cable anchor” issued Nov. 1, 1988 to Martin;
U.S. Pat. No. 4,909,231 entitled “Dual anchor cable separator for compound bows” issued Mar. 20, 1990 to Larson.
U.S. Pat. No. 5,381,777 entitled “Compound bow and yoke adjuster” issued Jan. 17, 1995 to Mitchell et al.
Examples of a split power cable arrangement for a compound bow are disclosed in the following patents, all of which are incorporated by reference as if fully set forth herein:
U.S. Pat. No. 5,390,655 entitled “Compound bow and cable mounting bracket” issued Feb. 21, 1995 to Mitchell et al;
U.S. Pat. No. 5,623,915 entitled “Archery bowstring system” issued Apr. 29, 1997 to Kudlacek;
U.S. Pat. No. 5,890,480 entitled “Dual-feed single-cam compound bow” issued Apr. 6, 1999 to McPherson;
U.S. Pat. No. 6,237,582 entitled “Archery bow with bow string coplanar with the longitudinal axis of the bow handle” issued May 29, 2001 to McPherson;
U.S. Pat. No. 6,474,324 entitled “Archery bows, archery bow cam assemblies, and archery bow anchors” issued Nov. 5, 2002 to Despart et al;
U.S. Pat. No. 6,659,096 entitled “Split-buss-cable single-cam compound archery bow” issued Dec. 9, 2003 to Nealy et al; and
U.S. Pat. No. 6,792,930 entitled “Single-cam split-harness compound bow” issued Sep. 21, 2004 to Kronengold et al.
Some compound bows include a mechanism on the bow limb for letting out the second end of the power cable. For example, bows disclosed in U.S. Pat. No. 3,990,425, U.S. Pat. No. 6,990,970, U.S. Pat. No. 7,305,979, and U.S. Pat. No. 7,441,555 include on a pulley member a journaled wheel (concentric or eccentric), a series of posts (from which the power cable unwinds), or an eccentrically located power cable attachment point. In some examples the second end (i.e., the let-out end) of the power cable directly engages the let out mechanism of the pulley member (as in FIGS. 1 and 2). In other examples the second end of the power cable is coupled to paired let-out mechanisms on opposite sides of the pulley member between the pulley member and the limb through a yoke or split-cable arrangement (as in FIGS. 3 and 4). The McPherson Series® Monster™ compound bow incorporates paired eccentrically located power cable attachment points (that include rotating-bearings) on the opposite sides of the pulley member between the pulley member and the bow limb, with a yoke arrangement coupling the second end of each power cable to the power cable attachment points.
An exemplary prior art dual-cam archery bow 20 (in this example employing a Binary Cam System®) is illustrated schematically in FIGS. 1 and 2. Bow limbs 211a and 211b extend oppositely from handle 210. Pulley members (i.e., cam assemblies) 230a and 230b are rotatably mounted on respective limbs 211a and 211b on respective axles 212a and 212b. Draw cable 240 is secured at each end to the cam assemblies 230a and 230b and received in respective draw cable journals 232a and 232b thereof. When the bow is drawn, the draw cable unwinds from the draw cable journals, thereby rotating the cam assemblies. A first power cable 245a is secured to the first cam assembly 230a and engaged with a power cable take-up journal 234a thereof, so that as the bow is drawn and the cam assembly 230a rotates, the power cable 245a is taken up by power cable take-up journal 234a of cam assembly 230a. The other end of power cable 245a is secured to cam assembly 230b and engaged with a power cable let-out journal 236b thereof, so that as the bow is drawn and cam assembly 230b rotates, power cable 245a is let out by power cable let-out journal 236b of cam assembly 230b. In an analogous fashion, power cable 245b is secured at one end to cam assembly 230b, engaged with a power cable take-up journal 234b thereof, and is taken up when the bow is drawn, while its other end is secured to cam assembly 230a, engaged with a power cable let-out journal 236a thereof, and is let out when the bow is drawn. The power cable take-up and let-out journals are arranged so that as the bow is drawn, the bow limbs are drawn toward one another. The power cables 245a and 245b are engaged at their second ends directly with the power cable let-out journals 236b and 236a, respectively.
Another exemplary prior art dual-cam archery bow 20 (similar to the McPherson Series® Monster™) is illustrated schematically in FIGS. 3 and 4. In this example the second end of the power cable 245a is coupled to paired, eccentrically located power cable attachment bearings 237a on the first cam assembly 230a by yoke cable 238a and yoke 239a. The second end of the power cable 235b is likewise coupled to power cable attachment bearings 237b on the second cam assembly 230b by yoke cable 238b and yoke 239b. The yoke cables 238a/b are secured to the attachment bearings 237a/b on opposite sides of the pulley members 230a/b, between each pulley member 230a/b and the corresponding bow limb 211a/b. 